In the welding of one pipe member to another it is conventional to apply to one of the pipe members adjacent one end thereof a clamp which carries a number of supports extending axially of the clamped pipe member and beyond the end of the latter so as to provide support for one end of a second pipe member that is to be joined to the clamped pipe member. Typical tools heretofore proposed for similar purposes are disclosed in Hickey U.S. Pat. No. 1,940,910; Robinson U.S. Pat. No. 2,108,077; Milton U.S. Pat. No. 2,127,828; Morris U.S. Pat. No. 2,674,966; Kinne U.S. Pat. No. 3,047,286; Phariss U.S. Pat. No. 3,414,950; Sehlman U.S. Pat. No. 3,422,519; Watson U.S. Pat. No. 3,467,295; Dearman U.S. Pat. No. 3,653,574; and Watson U.S. Pat. No. 3,666,159. Some of these tools are capable of use with pipes of different diameters, whereas others are not. Some of these tools are more quickly mounted on and removed from the pipes than are others, but each such tool requires more time than is desirable to mount it upon and remove it from the pipes.